A portable wireless communication receiver operates over a wide range of signal strengths and thus generally has some form of automatic gain control (AGC) system. Typical on-channel AGC systems are good at tracking slowly changing signal strength, but tend to be too slow for tracking sudden, large increases in signal strength, such as can occur during channel scanning. Such changes can temporarily saturate the mixers or baseband filters of the receiver, causing channel reception to be impaired until the on-channel AGC can recover.
One prior-art receiver attempted to solve the problem by adding a single, predetermined loss to the receiver front end in response to a sudden increase in wide-band energy. This approach, however, ultimately could not be used, because it made the receiver unstable under some signal conditions.
Thus, what is needed is a method and apparatus for mitigating a received power overload. The method and apparatus preferably will be able to respond quickly to a sudden, large increase in signal strength, such as can occur during channel scanning, without causing the receiver to become unstable.